mcp-server-semgrep/semgrep-rules/python/lang/correctness/list-modify-iterating.yaml

MCP Server for Semgrep Integration - static code analysis with AI

rules:
  - id: list-modify-while-iterate
    message: >-
      It appears that `$LIST` is a list that is being modified while in a for loop.
      This will likely cause a runtime error or an infinite loop.
    languages: [python]
    severity: ERROR
    pattern-either:
      - pattern: |
          for $ELEMENT in $LIST:
            ...
            $LIST.pop(...)
      - pattern: |
          for $ELEMENT in $LIST:
            ...
            $LIST.push(...)
      - pattern: |
          for $ELEMENT in $LIST:
            ...
            $LIST.append(...)
      - pattern: |
          for $ELEMENT in $LIST:
            ...
            $LIST.extend(...)
      - pattern: |
          for $ELEMENT in $LIST:
            ...
            $LIST.remove(...)
    metadata:
      category: correctness
      technology:
        - python
      references:
        - https://unspecified.wordpress.com/2009/02/12/thou-shalt-not-modify-a-list-during-iteration/